Conventionally, voice communication between different locations has occurred over a public switched telephone network (PSTN), which has proven to be a high quality and reliable medium for communication. However, when communicating via PSTNs from one local calling area to another, long distance toll charges are incurred. For businesses that have remote offices in various local calling areas and which require communication among the offices, significant long distance toll charges can accrue.
A proposed alternative to communicating voice over a PSTN is communicating voice over a packet network, such as a local area network (LAN) or wide area network (WAN). A widely used WAN is the Internet, which may be generally referred to as a voice over internet protocol (VOIP) network because of its voice communication capabilities. Information is communicated over the Internet in the form of a formatted unit of data called a packet using Transmission Control Protocol/Internet Protocol (TCP/IP). In a VOIP network, voice is packetized then communicated over the network. An advantage of communicating voice over the Internet is the elimination of long distance toll charges when communicating between different local calling areas. By using the Internet as the medium of communication for voice, businesses can save significant toll expenses. However, one drawback of the Internet is its unregulated access and indeterminate bandwidth.
Because vast numbers of computer users have access to the Internet, the amount of network traffic can increase substantially at certain times of the day and at any given moment, which may thereby overload the network. As a result, data packets being transported over the network may be delayed or even lost. The extent to which data packets are delayed or lost can be quantified to provide a relative quality of service (QOS) measure that indicates the suitability of the network to deliver packets in a timely and/or acceptable manner. Delayed delivery of data packets is not typically acceptable during a live conversation because the delay causes broken or staggered speech delivery. Consequently, when the network QOS is poor, the communicating parties are often forced to terminate their Internet-based call and to initiate more traditional telephone network-based calls.
To help remedy the QOS problem that may arise in an IP network, one type of voice communication system utilizes an IP network in combination with a PSTN. In this system, at the time of call initiation, the system determines whether the QOS of the IP network meets an acceptable QOS standard. If the QOS of the IP network is acceptable at call initiation, the call is routed via the IP network. Otherwise, the call is routed over the PSTN. While this system is helpful at the time of call initiation, this system does not remedy a reduction in the QOS for an Internet-based telephone call when the voice communication is in progress over the Internet. Consequently, in this type system, when the QOS for a voice communication unacceptably deteriorates during the communication, the communicating parties must terminate the IP-based telephone call and place another call via a PSTN.
Thus, there is a need for a system that enables an existing communication occurring over a WAN, such as an IP network, to be communicated in high quality manner when the quality of service of the WAN deteriorates.